Fluid heater



Feb. 14, 1939. M. A. zwMEFeMAN 2,147,610

FLUID HEATER Original Filed Dec. 28, 1935 2 Sheets-Sheet l I 8 I 30 27 G o o o 0 @@@@[D i @1 @@@J@@@ INVENTOR. Mar/e A. Zimmerman Feb. 14, 1939. M. A ZIMMERMAN 12,147,610

FLUID HEATER Original Filed Dec. 28, 1935 Figfz 2 Sheets-Sheet 2 INVENTOR. Merle A. Zimmerman ATTORNEY.

Patented Feb. 14, 1939 FLUID HEATER Merle A. Zimmerman, New York, N. Y., assignor to The Lummus Company, New York, N. Y., a corporation of Delaware Application December 28, 1935, Serial No. 56,126 Renewed January 6, 1939 6 Claims.

My invention relates to an improved form of tile, and particularly to tile adapted for use in conjunction with a row of fluid heating tubes to form a diffusion battle for heating gases flowing across the tube row.

The general object of my invention is the provision of tile of the type described which is further characterized by the resulting formation of gas passages in the diifusion baffle providing a uniform distribution of the heating gases across an associated tube row and an increased rate of heat transfer to the tubes in contact with the baffle tile. A further and more specific object is the provision of tube baffle tile which will effeet a high rate of heat transfer to the tube Wall portions over. which my improved tile extends.

The baiile tile of my invention is especially designed and particularly adapted for use in a diffusion baffle for an oil heater of the type shown in a prior application of Carl S. Reed and Vincent V17. Smith, Serial No. 632,154, filed Sept. 8, 1932.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advane ages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of my invention.

Of the drawings:

Fig. 1 is a sectional elevation of an oil heater incorporating my invention;

Fig. 2 is a part section taken at right angles to Fig. 1;

Fig. 3 is a section of one of my improved tile taken on the line 3--3 of Fig. 4;

Figs. 4 and 5 are plan and side views respectively of the tile shown in Fig. 3; and

Fig. 6 is a view similar to Fig. 3 of one of the end half-tiles.

In the drawings, and particularly in Figs. 1 and 2, is shown an oil heater of the type disclosed and claimed in said prior application of Carl S. Reed and Vincent W. Smith, and comprising a pair of opposite vertical side walls l0 extending between and closed by a second pair of opposite vertical side walls H, and a floor l2, collectively defining a box-shaped furnace chamber open at its top side or roof. Along the inner side of each side wall it extends a row of vertically spaced horizontally extending oil heating tubes l3 carried by longitudinally spaced supporting brackets 14 supported on the side wall. The end walls ll are refractory faced and mounted therein adjacent the floor 12 are symmetrically arranged fluid fuel burners [5, with corresponding burners ,in the opposite walls ll directed toward one an- The top side or roof of the furnace chamother. her is defined by two staggered rows of spaced oil heating tubes 26 and 2| arranged parallel to and of the same length as the wall tubes l3. The tubes 2 and 2| are supported in groups by spaced supporting means 22 swingably supported from the external steel work by pairs of hangers IE or 23.

With this construction of the furnace chamber, streams of burning fuel are discharged at oppo te ends thereof, the heatinggases generated passing upwardly towards the roof tubes and 2|. The tubes i3, 20 and 2| will thus absorb radiant heat from the furnace chamber, with the roof tubes 2|] absorbing much more radiant heat than the tubes 2!. The utilization of the entire roof area of the furnace chamber as a heating gas exit results in a low velocity gas flow past the row of tubes 20. This is especially desirable in an oil heater of this type so as to avoid excessive convection heat transfer to the tubes 20. To avoid local overheating of the tubes 2!! due to laning of the low velocity gases, a diffusion baffle 25, hereinafter described, is installed adjacent the upper row of tubes 2| with the passages therein uniformly distributed and of less aggregate flow area than the aggregate intertube area of the subjacent portions of the tubes 20, thereby providing a pressure drop at that level which will cause the heating gases to flow at a low velocity uniformly across the row of roof tubes 20. absorption along the length of the tubes 20 due to higher temperature conditions adjacent the center of the furnace chamber is largely compensated by radiation from the refractory faced walls II to the adjacent end portions of the tubes 20.

Above the diffusion baflle 25 is provided a flow equalizing or plenum chamber 26 in which the heating gases collect before entering the convection heating section of the heater. The con- Vection section is formed by a relatively shallow bank of staggered rows of oil heating tubes 21 extending parallel to and of the same length as the tubes I3, 20, and 2!. Effective heat transfer conditions for the tubes 2'! are maintained by causing a horizontal flow of the heating gases transversely of the tubes, and for this purpose a composite bafile 28 extends horizontally from one of the side walls H) across the heater immediately below the tubes 2,1. A heating gas out- Any variation in heat 2 let 29 controlled by one or more dampers 30 is formed in the wall l above the end of the baflle 28, so that heating gases entering the plenum chamber below the tubes 21 must first pass around the end of the baflle 28 and across the bank of tubes 21 before reaching the gas outlet 29. The oil to be heated enters the end of the tube bank 21 adjacent the outlet 29, then flows successively through the tubes 21, roof tubes 2|, roof tubes 20, and side wall tubes l3 in one or two streams, as may be desired.

While various types of diffusion bafiles have been suggested for the oil heater described, it has been found in practice that the most effective construction is obtained by employing refractory tile of the form shown in Figs. 3 to 6 in conjunction with the roof tubes 2|. As shown in Figs. 1, and 3 to 5, each tile piece 35 is rectangular in plan and formed with a flat top and bottom 36 and 31 respectively, and its opposite sides 38 concavely curved adjacent the bottom 3'! to fit against part of an upper quadrant of corresponding roof tubes 2|, so that each baffle tile will be supported at its sides on a pair of adjacent tubes 2 l. The tile pieces are arranged in rows extending longitudinally of the tubes 2| with corresponding tiles in adjacent rows having their side portions above the tubes 2| slightly spaced apart along the vertical axial plane of the common supporting tube as shown in Fig. 3.

The opposite ends 39 of each tile piece are shaped to permit overlapping of adjacent tiles in the same row, so as to minimize gas leakage between the tile ends. For this purpose, each tile piece has a tongue or top extension 40 at one end and a corresponding notch or shoulder 4| formed in the top at its opposite end, so that the tongue 40 of one tile will fit into the notch 4| of the next tile,

The gas passages through the diffusion baffle are uniformly distributed and arranged therein so as to increase the heat absorption of the supporting tubes 2|. The intermediate section of each curved lower side portion of the tile is recessed by curving it on a greater radius than the corresponding end sections so that each side 38 of the tile will have a pair of tube contacting concavely curved faces or ridges 38 and a concentric recess 3|! intermediate the ridges. When installed on the tubes 2|, a narrow arcuate passage 42 will be formed between each curved side portion of the tile and the upper quadrant of the corresponding contacted tube 2|. While the side portions extending above the tubes are slightly spaced from those of the corresponding tile in the adjacent rows, additional gas flow area is advantageously provided by recessing the vertical side portions of each tile in alignment with the sides of the recess 38*, as indicated at 43, to form when assembled uniformly spaced vertical passages 44 between the tile rows with each passage 44 connected at its bottom to a corresponding pair of arcuate passages 42. As shown in Figs. 1 and 6, only one side of the tile pieces in the end rows of the diffusion baflle is shaped to provide the described gas passages 42 and 44.

With the described diffusion bafile construction the heating gases passing at a low velocity across the lower row of roof tubes 20 will pass around the tubes 2| and through the arcuate passages 42 at a higher velocity, providing not only a high rate of heat transfer to the lower half of the tubes 2|, but also substantially increasing the amount of heat absorbed by the upper half of the tubes 2| in view of the direct contact of the high velocity heating gasestherewith. Additional heat is received by the upper half of the tubes 2| by secondary radiation from the passage-forming tile portions 38 and by conduction from the tube-contacting tile ridges 38, so that much of the heat absorbed by the tile will be transferred to the tubes 2| and the latter will be heated substantially uniformly throughout the circumference thereof. The heating gases leaving the passages 42 pass upwardly through the vertical passages 44 between the transversely adjacent tile. By way of example and not limitation, with the roof tubes 20 and 2| each having an outside diameter of and spaced on 11" centers and the tile in length by 10% in width, the passages 42 and 44 were A" in width and in width respectively, and 6 A" in length, thus providing a restricted gas flow area inducing a high gas velocity through the diffusion baffle passages.

While in accordance with the provisions of the statutes I have illustrated and described herein the best form of my invention now known to of horizontally extending heating tubes extending across said gas exit in transversely spaced relation and receiving radiant heat from said furnace chamber, a second adjoining row of heating tubes at the upper side of and staggered relative to said first row of tubes, and tile pieces supported on said second row of tubes and forming a diffusion bafile having uniformly distributed gas flow passages therein of less aggregate flow area than the aggregate intertube area of the subjacent portions of said first row of tubes, said tile pieces having a recessed portion along one side thereof concentric and cooperating with an adjacent tube portion to define opposite sides of a narrow curving gas flow passage.

2. A tubular oil heater comprising a furnace chamber having means for burning fuel therein and a heating gas exit occupying a major portion of the area of the roof thereof, adjoining uppei and lower rows of oil heating tubes extending across said gas exit in transversely spaced relation, said lower row of tubes being arranged to receive heat mainly by direct radiation from said furnace chamber, said upper row of tubes being staggered relative to said lower row of tubes, and tile pieces supported on said upper row of tubes and forming a diffusion baille having distributed gas flow passages therein, each of said tile pieces having a pair of longitudinally spaced concavely curved tube-contacting ridge portions extending transversely of at least one side thereof and a recessed portion extending longitudinally of said tile side intermediate said ridge portions and cooperating with the corresponding tube portion to define opposite sides of a heating gas passage therebetween.

3. A tubular oil heater comprising a furnace chamber having means for burning fuel therein and a heating gas exit occupying a major portion of the area of the roof thereof, adjoining upper and lower rows of horizontally extending oil heating tubes extending acrosssaid gas exit in transversely spaced relation, said lower row of tubes being arranged to receive heat mainly by direct radiation from said furnace chamber, said upper row of tubes being staggered relative to said lower row of tubes, and tile pieces supported on said upper row of tubes and forming a diffusion bafile having distributed gas flow passages therein of less aggregate flow area than the aggregate intertube area of the subjacent portions of said lower row of tubes, each of said tile pieces having a pair of longitudinally spaced concavely curved tube-contacting ridge portions extending transversely of each side thereof and a recessed portion extending longitudinally of each tile side intermediate said ridge portions and cooperating with the corresponding wall portions of said tubes to define opposite sides of heating gas passages therebetween, each having a lower section curving around an upper quadrant of the corresponding tube and a vertical section above said tube.

4. A petroleum oil heater comprising a main combustion chamber, a row of fluid heating tubes in the roof thereof, which tubes are spaced so as to produce a low convection heat transfer thereto, a second row of fluid heating tubes above the first row of tubes, tile pieces supported on said second row of tubes and forming a diffusion bafile across the top of said second row of tubes, said tile pieces having a plurality of recessed portions extending from their top walls to their bottom walls and between adjacent tile pieces, said recessed portions being relatively shallow to effect a substantial pressure drop in the gases flowing across said second row of tubes and between said tile pieces, whereby the flow of gases is made substantially uniform across the entire first row of tubes, a flow equalizing chamber above the tile pieces, and a bank of fluid heating tubes in a convection chamber which leads from the flow equalizing chamber.

5. A fluid heater comprising a furnace chamber having a heating gas exit in the roof thereof, a horizontal row of well-spaced fluid heating tubes extending across said exit and positioned to receive mainly radiant heat from said furnace chamber, a second row of fluid heating tubes at the upper side of said first row of tubes, tile pieces supported on said second row of tubes to form a diffusion bafiie, said tile pieces each having a recessed portion along one side thereof concentric and cooperating with an adjacent tube portion to define opposite sides of curving gas flow passages, said tile pieces each including a plurality of relatively small edge recesses which with the adjacent tile pieces and the recessed portions which are concentric with the tubes, form continuous gas flow passages, said passages being relatively small to establish a substantial pressure drop across the tubes for creating a uniform flow across all of the tubes in the first row extending across said exit, a plenum chamber beyond the tile pieces, and a bank of convectively heated tubes beyond the plenum chamber.

6. An oil heater comprising a furnace chamber having a heating gas exit in the roof thereof, a row of oil heating tubes extending across said exit, said tubes being spaced so as to produce a relatively low convection heat transfer thereto, a second row of oil heating tubes arranged above and staggered relative to the first row of tubes, tile pieces supported on and extending along said second row of tubes and forming a diffusion baffle across the top of said tubes, said tile pieces having a plurality of relatively shallow recessed portions extending from their top walls to their bottom walls and forming narrow gas flow passages between said tile pieces and second row tubes and between laterally adjacent tile pieces to effect a substantial pressure drop in the gases flowing across said second row of tubes and between said tile pieces, whereby the flow of gases is made substantially uniform across all of the tubes in said first row extending across said exit, a flow equalizing chamber beyond the tile pieces, and a bank of convectively heated oil heating tubes beyond and in a gas passage connected to the flow equalizing chamber.

MERLE A. ZIMMERMAN.

CERTIFICATE OF- CORRECTION. Patent No. 2,111,75610. February 11 1959.

HERE A. ZINIIERITAN It is hereby certified that error-appears ii: the printed specification of the above mmibered patent requirihg correction as follows; Page 2, first column, line 29, afterthe word "tube" ihs ert the numeral 21; and seco'nd column, line 57, claim l, for "radiant heat" read heat mainly-by direct radiation; and that the said Letters Patent shouldbe read with this cor-'- rection therein that the same may conform to the record of the ease in the Patent Office;

Signed and sealed this 18th day or April, A. D. 1959.

Henry Van Arsdale (Seal) Acting Commissioner of Patents. 

